1. Field of the Invention
This invention relates to a horizontal deflection circuit suitable for use in a raster-scanned cathode-ray-tube, such as that found in most television receivers.
2. Description of the Prior Art
A circuit in which a DC current is turned on and off by a switching element to produce a regulated DC voltage as a supply voltage for a horizontal deflection circuit is disclosed by Mr. Peter L. Wessel in the publication "IEEE Transactions on Broadcast and Television Receivers", August 1972, vol. BRT-18, No. 3, at pages 177 to 182. This circuit (hereinafter referred to as a Wessel's circuit) is the combination of a horizontal deflection circuit and a voltage supply circuit, in which a switching transistor used as the switching element in the deflecting circuit is also used as the switching element in the voltage supply circuit. The Wessel's circuit has the advantage that it can be fed by an unstabilized supply voltage and can produce a stabilized deflection current and a stabilized high voltage. On the other hand, however, this circuit has the drawback that considerable power is required for producing the high voltage since it supplies power to its high voltage winding solely from its regulated voltage supply circuit; meaning that all of the power which is supplied to the high voltage winding must first pass through a switching power supply transformer, with its inevitable power losses. In addition, a high inductance is required for the windings of the switching power supply transformer resulting in a high cost. Further, this circuit causes a relatively large DC current to pass through the switching element decreasing the efficiency of the whole circuit.